Virtual Colonoscopy is a relatively new field in medicine and consists in processing the computer tomographic (CT) image planes or “slices” of the patient rather than the traditional and invasive colonoscopic inspection. By segmenting the original parallel CT slices, it is possible to reconstruct the 3D surface of the colon and thus provide the information needed for Colonoscopy. Such a process is disclosed in Summers et al. U.S. Pat. No. 6,246,748 issued Jun. 12, 2001 and entitled Method for Segmenting Medical Images and Detecting Surface Anomalies in Anatomical Structures. This disclosure assumes as a starting point that an image similar to that produced by Summers et al '748 is produced.
Assuming the presence of such an image, further processing of the image such as detecting the centerline of the colon is still a challenging problem. The following articles are representative of relevant image processing techniques that can be used to address this problem:
Gabriel Taubin, “Curve and Surface Smoothing without Shrinkage”, IEEE (1995);
Ingmar Bitter, et al., “Penalized-Distance Volumetric Skeleton Algorithm”, IEEE Transactions on Visualization and Computer Graphics, Vol.7, No. 3, July-September 2001;
Ge, Y., D. R. Stelts, et al., “Computing the centerline of a colon; a robust and efficient method based on 3D skeletons”, J Comput Assist Tomogr, 23(5): 786-94 (1999);
Jie Wang, Yaorong Ge, “An Optimization problem in Virtual Colonoscopy”, Theoretical Computer Science, Elsevier Science B. V., pp 203-216 (1998);
Yaorong Ge, et al., “Computing the Centerline of a Colon: a Robust and Efficient Method Based on 3D Skeletons”, Journal of Computer Assisted Tomography, 23(5):786-794 (1999);
Rui Chiou, et al., “An Interactive Fly-Path Planning Using Potential Fields and Cell Decomposition for Virtual Endoscopy”, IEEE Transactions on Nuclear Science, Vol 46, No. 4, Aug. 1999;
David Paik, et al., “Automated flight path planning for virtual endoscopy”, American Assoc Of Physicists in Medicine (1998);
C. L. Wyatt, et al., “Automatic Segmentation of the Colon for Virtual Colonoscopy”, Elsevier Science (2000);
Elisabeth McFarland, et al., “Spiral Computed Tomographic Colonography: Determination of the Central Axis and Digital Unravelling of the Colon”, Technical Report, Acad. Radiology, 4:367-373 (1997);
Roel Truyen, et al., “Efficacy of automatic path tracking in Virtual colonoscopy”, Cars 2001—H. U Lemke, et al. (Editors), Elsevier Science (2001).
C. E. Shannon, “A Mathematical Theory of Communication”, Bell System Tech. J, 379-423 (1948); and
W. J. Schroeder, et al., “Decimation of Triangle Meshes”, Computer Graphics, 26:26 (1992).
The reader will understand that the colonoscope is the usual instrument used both for inspection and surgery of the colon. The measurements of the colon must be all related to the path of the colonoscope, always from the rectum. In making its penetration of the colon, the colon “gathers” the invading colonoscope into the serpentine path of the major axis of the colon while the colonoscope “hunts” this path within the confines of the colon. As a consequence of this well known and understood technique of using a colonoscope, relevant measurements taken with respect to the colon by non-invasive CT scans must all be related to penetration of a colonoscope.
Further, scans taken by a colonoscope must be able to be compared to non-invasive scans taken by computer tomography to establish the efficacy of the non-invasive scans. Likewise, and assuming efficacy of the non-invasive scans, the findings of the non-invasive scans must be directly translatable to the doctor using colonoscope to be of practical value.